<?php

namespace extend\wechat;

use think\Cache;

class JsSDK
{
    private $appId;
    private $appSecret;

    const access_token_key = 'wechat_access_token';
    const ticket_key = 'wechat_tiket_token';

    public function __construct($appId = '', $appSecret = '')
    {
        $this->appId = isset($appId) ? $appId : \Config::get('wechat.appid');
        $this->appSecret = isset($appSecret) ? $appSecret : \Config::get('wechat.ak');
    }

    public function getSignPackage()
    {
        $jsapiTicket = $this->getJsApiTicket();
        $protocol = (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off' || $_SERVER['SERVER_PORT'] == 443) ? "https://" : "http://";
        $url = "$protocol$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]";
        $timestamp = time();
        $nonceStr = $this->createNonceStr();

        // 这里参数的顺序要按照 key 值 ASCII 码升序排序
        $string = "jsapi_ticket=$jsapiTicket&noncestr=$nonceStr&timestamp=$timestamp&url=$url";

        $signature = sha1($string);

        $signPackage = array(
            "appId" => $this->appId,
            "nonceStr" => $nonceStr,
            "timestamp" => $timestamp,
            "url" => $url,
            "signature" => $signature,
            "rawString" => $string
        );
        return $signPackage;
    }

    private function createNonceStr($length = 16)
    {
        $chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
        $str = "";
        for ($i = 0; $i < $length; $i++) {
            $str .= substr($chars, mt_rand(0, strlen($chars) - 1), 1);
        }
        return $str;
    }

    private function getJsApiTicket()
    {
        // jsapi_ticket 应该全局存储与更新，以下代码以写入到文件中做示例
        $access_token = Cache::get(self::ticket_key);
        $data = json_decode($access_token, true);
        if (empty($data) || $data['expire_time'] < time()) {
            $accessToken = $this->getAccessToken();
            // 如果是企业号用以下 URL 获取 ticket
            // $url = "https://qyapi.weixin.qq.com/cgi-bin/get_jsapi_ticket?access_token=$accessToken";
            $url = "https://api.weixin.qq.com/cgi-bin/ticket/getticket?type=jsapi&access_token=$accessToken";
            $res = json_decode($this->httpGet($url));
            $ticket = $res->ticket;
            if ($ticket) {
                $data['expire_time'] = time() + 7000;
                $data['jsapi_ticket'] = $ticket;
                $access_token = json_encode($data);
                Cache::set(self::ticket_key, $access_token, 7199);
            }
        } else {
            $ticket = $data['jsapi_ticket'];
        }

        return $ticket;
    }

    private function getAccessToken()
    {
        // access_token 应该全局存储与更新，以下代码以写入到文件中做示例
        $access_token = Cache::get(self::access_token_key);
        $data = json_decode($access_token,true);
        if (empty($data) || $data['expire_time'] < time()) {
            // 如果是企业号用以下URL获取access_token
            // $url = "https://qyapi.weixin.qq.com/cgi-bin/gettoken?corpid=$this->appId&corpsecret=$this->appSecret";
            $url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=$this->appId&secret=$this->appSecret";
            $res = json_decode($this->httpGet($url));
            $access_token = $res->access_token;
            if ($access_token) {
                $data['expire_time'] = time() + 7000;
                $data['access_token'] = $access_token;
                $access_token = json_encode($data);
                Cache::set(self::access_token_key, $access_token, 7199);
            }
        } else {
            $access_token = $data['access_token'];
        }
        return $access_token;
    }

    private function httpGet($url)
    {
        $curl = curl_init();
        curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($curl, CURLOPT_TIMEOUT, 500);
        curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);
        curl_setopt($curl, CURLOPT_URL, $url);

        $res = curl_exec($curl);
        curl_close($curl);

        return $res;
    }
}
